The NSR is normaly cheaper about £2500 - £2700 you could expect to pay but the RS 125 is around £3500 from new but for your extra £700 you get about an extra 30mph (with a full power RS) dont even bother derestricting a NSR you´ll pop the engin in 3months if you do. your looking at about 90mph - 100mph for the NSR